(possible implicit) noexcept specifier
Throwing in the destructor is not good (C++11 change try to not allow see below).
But in reality, those codes are exist.
C++11 [class.dtor]p3:
A declaration of a destructor that does not have an exception-specification is
implicitly considered to have the same exception specification as an implicit
declaration.
With this change, the application worked before may now run into runtime
termination. My goal here is to emit a warning to provide only possible info to
where the code may need to be changed.
First there is no way, in compile time to identify the “throw” really throw out
of the function. Things like the call which throw out… To keep this simple,
when “throw” is seen, checking its enclosing function(only destructor and
dealloc functions) with noexcept(true) specifier emit warning.
Here is implementation detail:
A new member function CheckCXXThrowInNonThrowingFunc is added for class Sema
in Sema.h. It is used in the call to both BuildCXXThrow and
TransformCXXThrowExpr.
The function basic check if the enclosing function with non-throwing noexcept
specifer, if so emit warning for it.
The example of warning message like:
k1.cpp:18:3: warning: ''~dependent_warn'' has a (possible implicit) non-throwing
noexcept specifier. Throwing exception may cause termination.
[-Wthrow-in-dtor]
throw 1;
^
k1.cpp:43:30: note: in instantiation of member function
'dependent_warn<noexcept_fun>::~dependent_warn' requested here
dependent_warn<noexcept_fun> f; // cause warning
Differential Revision: https://reviews.llvm.org/D33333
llvm-svn: 306149
CheckSingleAssignmentConstraints. These no longer produce ExprError() when they
have not emitted an error, and reliably inform the caller when they *have*
emitted an error.
This fixes some serious issues where we would fail to emit any diagnostic for
invalid code and then attempt to emit code for an invalid AST, and conversely
some issues where we would emit two diagnostics for the same problem.
llvm-svn: 283508
Replace inheriting constructors implementation with new approach, voted into
C++ last year as a DR against C++11.
Instead of synthesizing a set of derived class constructors for each inherited
base class constructor, we make the constructors of the base class visible to
constructor lookup in the derived class, using the normal rules for
using-declarations.
For constructors, UsingShadowDecl now has a ConstructorUsingShadowDecl derived
class that tracks the requisite additional information. We create shadow
constructors (not found by name lookup) in the derived class to model the
actual initialization, and have a new expression node,
CXXInheritedCtorInitExpr, to model the initialization of a base class from such
a constructor. (This initialization is special because it performs real perfect
forwarding of arguments.)
In cases where argument forwarding is not possible (for inalloca calls,
variadic calls, and calls with callee parameter cleanup), the shadow inheriting
constructor is not emitted and instead we directly emit the initialization code
into the caller of the inherited constructor.
Note that this new model is not perfectly compatible with the old model in some
corner cases. In particular:
* if B inherits a private constructor from A, and C uses that constructor to
construct a B, then we previously required that A befriends B and B
befriends C, but the new rules require A to befriend C directly, and
* if a derived class has its own constructors (and so its implicit default
constructor is suppressed), it may still inherit a default constructor from
a base class
llvm-svn: 274049
specification) to an error. No compiler other than Clang seems to allow this,
and it doesn't seem like a useful thing to accept as an extension in general.
The current behavior was added for PR5957, where the problem was specifically
related to mismatches of the exception specification on the implicitly-declared
global operator new and delete. To retain that workaround, we downgrade the
error to an ExtWarn when the declaration is of a replaceable global allocation
function.
Now that this is an error, stop trying (and failing) to recover from a missing
computed noexcept specification. That recovery didn't work, and led to crashes
in code like the added testcase.
llvm-svn: 248867
Currently we emit DeferredDeclsToEmit in reverse order. This patch changes that.
The advantages of the change are that
* The output order is a bit closer to the source order. The change to
test/CodeGenCXX/pod-member-memcpys.cpp is a good example.
* If we decide to deffer more, it will not cause as large changes in the
estcases as it would without this patch.
llvm-svn: 226751
than the type of a function declaration). We previously didn't instantiate
these at all! This also covers the pathological case where the only mention of
a parameter pack is within the exception specification; this gives us a second
way (other than alias templates) to reach the horrible state where a type
contains an unexpanded pack, but its canonical type does not.
This is a re-commit of r219977:
r219977 was reverted in r220038 because it hit a wrong-code bug in GCC 4.7.2.
(That's gcc.gnu.org/PR56135, and affects any implicit lambda-capture of
'this' within a template.)
r219977 was a re-commit of r217995, r218011, and r218053:
r217995 was reverted in r218058 because it hit a rejects-valid bug in MSVC.
(Incorrect overload resolution in the presence of using-declarations.)
It was re-committed in r219977 with a workaround for the MSVC rejects-valid.
r218011 was a workaround for an MSVC parser bug. (Incorrect desugaring of
unbraced range-based for loop).
llvm-svn: 221750
It broke some builders. I guess it'd be reproducible with --vg.
Failing Tests (3):
Clang :: CXX/except/except.spec/p1.cpp
Clang :: SemaTemplate/instantiate-exception-spec-cxx11.cpp
Clang :: SemaTemplate/instantiate-exception-spec.cpp
llvm-svn: 220038
reverted in r218058 because they triggered a rejects-valid bug in MSVC.
Original commit message from r217995:
Instantiate exception specifications when instantiating function types (other
than the type of a function declaration). We previously didn't instantiate
these at all! This also covers the pathological case where the only mention of
a parameter pack is within the exception specification; this gives us a second
way (other than alias templates) to reach the horrible state where a type
contains an unexpanded pack, but its canonical type does not.
llvm-svn: 219977
r218053: Use exceptions() instead of getNumExceptions()/getExceptionType() to avoid
r218011: Work around MSVC parser bug by putting redundant braces around the body of
r217997: Skip parens when detecting whether we're instantiating a function declaration.
r217995: Instantiate exception specifications when instantiating function types (other
The Windows build was broken for 16 hours and no one had any good ideas of how to
fix it. Reverting for now to make the builders green. See the cfe-commits thread [1] for
more info.
This was the build error (from [2]):
C:\bb-win7\ninja-clang-i686-msc17-R\llvm-project\clang\lib\Sema\SemaTemplateInstantiate.cpp(1590) : error C2668: '`anonymous-namespace'::TemplateInstantiator::TransformFunctionProtoType' : ambiguous call to overloaded function
C:\bb-win7\ninja-clang-i686-msc17-R\llvm-project\clang\lib\Sema\SemaTemplateInstantiate.cpp(1313): could be 'clang::QualType `anonymous-namespace'::TemplateInstantiator::TransformFunctionProtoType<clang::Sema::SubstFunctionDeclType::<lambda_756edcbe7bd5c7584849a6e3a1491735>>(clang::TypeLocBuilder &,clang::FunctionProtoTypeLoc,clang::CXXRecordDecl *,unsigned int,Fn)'
with
[
Fn=clang::Sema::SubstFunctionDeclType::<lambda_756edcbe7bd5c7584849a6e3a1491735>
]
c:\bb-win7\ninja-clang-i686-msc17-r\llvm-project\clang\lib\sema\TreeTransform.h(4532): or 'clang::QualType clang::TreeTransform<Derived>::TransformFunctionProtoType<clang::Sema::SubstFunctionDeclType::<lambda_756edcbe7bd5c7584849a6e3a1491735>>(clang::TypeLocBuilder &,clang::FunctionProtoTypeLoc,clang::CXXRecordDecl *,unsigned int,Fn)'
with
[
Derived=`anonymous-namespace'::TemplateInstantiator,
Fn=clang::Sema::SubstFunctionDeclType::<lambda_756edcbe7bd5c7584849a6e3a1491735>
]
while trying to match the argument list '(clang::TypeLocBuilder, clang::FunctionProtoTypeLoc, clang::CXXRecordDecl *, unsigned int, clang::Sema::SubstFunctionDeclType::<lambda_756edcbe7bd5c7584849a6e3a1491735>)'
1. http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20140915/115011.html
2. http://bb.pgr.jp/builders/ninja-clang-i686-msc17-R/builds/10515/steps/build_clang_tools_1/logs/stdio
llvm-svn: 218058
than the type of a function declaration). We previously didn't instantiate
these at all! This also covers the pathological case where the only mention of
a parameter pack is within the exception specification; this gives us a second
way (other than alias templates) to reach the horrible state where a type
contains an unexpanded pack, but its canonical type does not.
llvm-svn: 217995
Because references must be initialized using some evaluated expression, they
must point to something, and a callee can assume the reference parameter is
dereferenceable. Taking advantage of a new attribute just added to LLVM, mark
them as such.
Because dereferenceability in addrspace(0) implies nonnull in the backend, we
don't need both attributes. However, we need to know the size of the object to
use the dereferenceable attribute, so for incomplete types we still emit only
nonnull.
llvm-svn: 213386
'operator delete' or 'operator delete[]' is an explicit exception
specification. Therefore we should diagnose 'void operator delete(void*)'
instead of 'void operator delete(void*) noexcept'.
This diagnostic remains an ExtWarn, since in practice people don't always
include the exception specification in such a declaration.
llvm-svn: 201002
Implement type trait primitives used in the latest edition of the Microsoft
standard C++ library type_traits header.
With this change we can parse much of the Visual Studio 2013 standard headers,
particularly anything that includes <type_traits>.
Fully implemented, available in all language modes:
* __is_constructible()
* __is_nothrow_constructible()
* __is_nothrow_assignable()
Partially implemented, semantic analysis WIP, available as MS extensions:
* __is_destructible()
* __is_nothrow_destructible()
llvm-svn: 199619
Exception specs are not part of the canonical type, but we shouldn't
drop them just because we merged a noreturn attribute.
Fixes PR17110.
llvm-svn: 190206
statement in constexpr functions. Everything which doesn't require variable
mutation is also allowed as an extension in C++11. 'void' becomes a literal
type to support constexpr functions which return 'void'.
llvm-svn: 180022
constructor. This isn't quite perfect (as usual, we don't handle default
arguments correctly yet, and we don't deal with copy/move constructors for
arguments correctly either, but this will be fixed when we implement core issue
1351.
This completes our support for inheriting constructors.
llvm-svn: 179154
since it also has an implicit exception specification. Downgrade the error to
an extwarn, since at least for operator delete, system headers like to declare
it as 'noexcept' whereas the implicit definition does not have an explicit
exception specification. Move the exception specification for user-declared
'operator delete' functions from the type-as-written into the type, to reflect
reality and to allow us to detect whether there was an implicit exception spec
or not.
llvm-svn: 166372
Disambiguate past such a potential problem, and use the absence of 'typename'
to break ties in favor of a parenthesized thingy being an initializer, if
nothing else in the declaration disambiguates it as declaring a function.
llvm-svn: 156963
We have a new flavor of exception specification, EST_Uninstantiated. A function
type with this exception specification carries a pointer to a FunctionDecl, and
the exception specification for that FunctionDecl is instantiated (if needed)
and used in the place of the function type's exception specification.
When a function template declaration with a non-trivial exception specification
is instantiated, the specialization's exception specification is set to this
new 'uninstantiated' kind rather than being instantiated immediately.
Expr::CanThrow has migrated onto Sema, so it can instantiate exception specs
on-demand. Also, any odr-use of a function triggers the instantiation of its
exception specification (the exception specification could be needed by IRGen).
In passing, fix two places where a DeclRefExpr was created but the corresponding
function was not actually marked odr-used. We used to get away with this, but
don't any more.
Also fix a bug where instantiating an exception specification which refers to
function parameters resulted in a crash. We still have the same bug in default
arguments, which I'll be looking into next.
This, plus a tiny patch to fix libstdc++'s common_type, is enough for clang to
parse (and, in very limited testing, support) all of libstdc++4.7's standard
headers.
llvm-svn: 154886
value of class type, look for a unique conversion operator converting to
integral or unscoped enumeration type and use that. Implements [expr.const]p5.
Sema::VerifyIntegerConstantExpression now performs the conversion and returns
the converted result. Some important callers of Expr::isIntegralConstantExpr
have been switched over to using it (including all of those required for C++11
conformance); this switch brings a side-benefit of improved diagnostics and, in
several cases, simpler code. However, some language extensions and attributes
have not been moved across and will not perform implicit conversions on
constant expressions of literal class type where an ICE is required.
In passing, fix static_assert to perform a contextual conversion to bool on its
argument.
llvm-svn: 149776
This model uses the 'landingpad' instruction, which is pinned to the top of the
landing pad. (A landing pad is defined as the destination of the unwind branch
of an invoke instruction.) All of the information needed to generate the correct
exception handling metadata during code generation is encoded into the
landingpad instruction.
The new 'resume' instruction takes the place of the llvm.eh.resume intrinsic
call. It's lowered in much the same way as the intrinsic is.
llvm-svn: 140049
in a noexcept exception specification because it isn't part of the
canonical type. This ensures that we keep the exact expression written
in the noexcept exception specification, rather than accidentally
"adopting" a previously-written and canonically "equivalent" function
prototype. Fixes PR10087.
llvm-svn: 132998
to be careful to emit landing pads that are always prepared to handle a
cleanup path. This is correct mostly because of the fix to the LLVM
inliner, r132200.
llvm-svn: 132209
Erich Keane